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CPM Calculator

See what 1,000 impressions cost, and what a click cost when you add clicks.

Total spend for the period, in one currency.

Served impressions for the same period. Must be greater than zero.

Clear

CPM

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Cost per 1,000 impressions

cost ÷ impressions × 1,000

Enter cost and impressions. An empty field is not zero.

CPC
Add clicks

How a CPM is worked out

Spend and delivered impressions go in. The price of 1,000 impressions comes out, plus the price of a click when you add clicks.

  1. Enter the cost

    Type what the buy cost for the period, in one currency. Keep fees in or out the same way each time.

  2. Enter impressions

    Use the impressions delivered for that spend, from the ad server or the invoice.

  3. Add clicks if you have them

    Clicks are optional. With a count above zero, the readout adds CPC, the cost of one click.

  4. Check the working

    The formula line repeats your numbers: cost ÷ impressions × 1,000, rounded to four decimal places.

Impressions per CPM unit
1,000
Decimal places on CPM and CPC
4
Optional field: clicks, for CPC
1
Characters allowed in the currency label
12

What you get back

One readout with the CPM on top and a CPC row underneath.

  • CPM

    The cost of 1,000 impressions for the spend and delivery you enter, to four decimal places.

    cost ÷ impressions × 1,000

  • CPC

    The cost of one click, added to the readout when the clicks field holds a number above zero.

    cost ÷ clicks

  • Formula line

    Cost and impressions as read, with thousands separators, then × 1,000 and the CPM.

  • Currency label

    An optional tag such as EUR, shown after the unit line. The figures stay in whatever currency you typed.

  • CPC row wording

    Add clicks while the field is blank, Undefined when clicks are 0, and a dash while there is no CPM.

  • Field errors

    A negative, a comma or text marks the field in red, and the message names it: Cost, Impressions or Clicks.

One campaign priced per thousand and per click

The worked example uses made-up numbers for one campaign flight. It prices the same spend three ways, then blends two line items.

  1. CPM

    1,350 spread over 450,000 impressions is 0.003 per impression, or 3.0000 per 1,000.

  2. CPC

    The same 1,350 over 900 clicks is 1.5000 per click. Both figures keep four decimal places.

  3. CTR ties them together

    CPM = CPC × CTR as a decimal × 1,000. With two of the three known, the third follows by division.

  4. Blending line items

    Add the costs and the impressions, then divide once. Averaging 3.00 and 8.00 gives 5.50, which overstates this buy by more than half.

How CPM lines up with CPC, eCPM and RPM

The calculator works in one direction, from cost to CPM and CPC. The rearrangements below are arithmetic on the same formula.

Cost of a planned volume
Cost = CPM × impressions ÷ 1,000. At a 4.00 CPM, 250,000 impressions cost 1,000.
Impressions a budget buys
Impressions = cost ÷ CPM × 1,000. A budget of 600 at a 2.50 CPM buys 240,000 impressions.
CPC from CPM and CTR
CPC = CPM ÷ (CTR as a decimal × 1,000). A 3.00 CPM at a 0.2% CTR works out to a 1.50 CPC.
Effective CPM of another buy
For a buy priced per click or per action, total cost ÷ impressions × 1,000 is its effective CPM. A per-click buy that spent 390 on 260,000 impressions ran at 1.50.
CPM next to the seller's RPM
The seller measures revenue per 1,000 impressions or pageviews. Fees and revenue shares sit between the two, so the buyer's CPM and the seller's RPM for the same impressions differ.

Reading a result

The readout has the same parts on every run. This one shows a finished CPM with clicks filled in.

  1. Label

    CPM, the price of 1,000 impressions.

  2. Figure

    Four decimal places. A dash while a field is empty or invalid, or while impressions are 0.

  3. Unit line

    Cost per 1,000 impressions, then your currency label after a dot.

  4. Formula line

    Cost and impressions as read, with thousands separators and up to six decimals, then × 1,000 and the CPM. Before both are in, it reads cost ÷ impressions × 1,000.

  5. CPC row

    Cost ÷ clicks to four decimal places. Blank clicks show Add clicks; zero clicks show Undefined, with a note underneath.

Result states

The CPM figure and the CPC row each have their own states. The names below match the workbench wording.

Result What it means What to do next
CPM
Cost and impressions are numbers and impressions are above zero. The figure is the cost of 1,000 impressions.
Hold it against the quoted rate, or add clicks for CPC.
CPC
The clicks field holds a number above zero. The CPC row shows cost ÷ clicks to four decimal places.
Enter the same clicks and impressions in the CTR Calculator to see the click rate.
Add clicks
The clicks field is blank. The CPM still shows; the CPC row waits for a count.
Leave it blank when you only need CPM.
Undefined
Clicks are 0. A cost spread over no clicks has no price per click, and a note reads “CPC is undefined when clicks are zero.”
Check that the clicks come from the same report and dates as the impressions.
Enter cost and impressions
Cost or impressions is blank. The CPM waits with a dash, and the line under it ends “An empty field is not zero.” A form sent without JavaScript comes back with “Cost is required. Empty is not zero.”
Fill both fields from the same flight.
Cannot compute: impressions must be greater than zero
Impressions are 0, so there is no price per 1,000. If clicks are filled in, the CPC row shows a dash as well.
Take impressions from the delivery report for the same dates as the cost.
Cannot compute with these numbers
Both numbers pass the checks, yet the answer overflows what the calculator can store. A cost of 1e308 does it.
Check the cost field for an exponent or extra digits.
Cost must be a finite non-negative number
The entry holds a minus sign, a comma, a symbol or text. Impressions and Clicks get the same message under their own name.
Type plain digits, such as 2475 or 0.75.

Where cost and delivery numbers come from

The calculator reads only what you type. A CPM is as sound as the match between the cost and the impressions it covers.

CostInvoice
What was paid for the flight: the invoice total or the spend in the buying platform. Treat fees the same way in every cost you compare.
ImpressionsDelivery report
Impressions delivered for that spend. When the seller's count and your ad server's count differ, use the one the price was agreed on.
ClicksOptional
Clicks from the same report and dates. Leave the field blank if the report has none.
Flight datesYour choice
Nothing on the form holds a date. Cost, impressions and clicks must describe the same flight.
CurrencyLabel only
The label only tags the unit line. Quotes in two currencies need converting before they share a scale.

What moves a CPM

CPM moves when spend or delivery changes. These are common reasons a delivered CPM drifts from the quote.

Fees in the cost
Adding platform or agency fees raises CPM for the same impressions. Leaving them out lowers it.
Counting rule
Served, rendered and viewable impressions are different counts. The smaller the count, the higher the CPM for the same spend.
Filtered traffic
If some impressions are later removed as invalid, the same cost covers fewer of them and CPM rises.
Pricing model
A flat fee or a per-click buy has no quoted CPM. Its effective CPM depends on how many impressions the spend delivered.
Flight length
A month of cost over three weeks of impressions produces a CPM that no buy ever had.

What to enter

Non-negative numbers for one flight. Clicks may stay blank; cost and impressions may not.

Accepted

  • 2475

    Whole amounts and counts as plain digits.

  • 0.75

    Costs below one unit.

  • 4.5e5

    Scientific notation, read as 450,000.

  • 0

    A cost of 0 gives a CPM of 0.0000, as with bonus impressions.

Read as

  • 450000becomes450,000

    The formula line adds thousands separators.

  • +900becomes900

    A leading plus sign is dropped, and spaces around a number are trimmed.

  • 3.14159265becomes3.141593

    The formula line rounds inputs to six decimals for display. The math uses the full number.

Not accepted

  • 2,475

    A comma makes the entry invalid. Type 2475.

  • €2475

    Currency symbols belong in the currency label.

  • -900

    Negative costs, impressions or clicks are rejected.

  • n/a

    Text is not a number. Leave clicks blank instead.

Worked scenarios

Four jobs a buyer or a seller brings to the calculator. The numbers are made up; the readout wording is exact.

Checking an invoice

Cost 2475 · Impressions 550000
You see
CPM 4.5000. Formula line 2,475 ÷ 550,000 × 1,000 = 4.5000.
What it means
The flight cost 4.50 per 1,000 delivered impressions, the figure to hold against the insertion order.
Next
If the quote was lower, compare delivered impressions with the booked volume.

Two quotes on one scale

Cost 500 · Impressions 125000
You see
CPM 4.0000. A second run with 900 for 300,000 impressions reads 3.0000.
What it means
The larger package costs more in total and less per 1,000 impressions.
Next
Confirm both sellers count impressions the same way before choosing.

Adding clicks for CPC

Cost 640 · Impressions 320000 · Clicks 256
You see
CPM 2.0000 and CPC 2.5000.
What it means
Each click cost 2.50. The ad drew 256 clicks in 320,000 impressions.
Next
Enter the same clicks and impressions in the CTR Calculator to read that as 0.0800%.

A flight with no clicks

Cost 150 · Impressions 60000 · Clicks 0
You see
CPM 2.5000. The CPC row reads Undefined, with “CPC is undefined when clicks are zero.”
What it means
The spend bought impressions and no clicks, so there is no price per click.
Next
Leave clicks blank for awareness buys where only CPM matters.

Before you hold a CPM against a quote

Two CPMs compare only when they were built the same way.

  1. The agreed impression count

    Use the count the price was set on: served, rendered or viewable.

  2. Fees on both sides

    Include or leave out platform and agency fees in both the quote and the delivered cost.

  3. Totals before division

    Add cost and impressions across line items before dividing. An average of CPMs gives small buys too much weight.

  4. One flight

    Cost and impressions should start and end on the same dates.

  5. One currency

    Convert before you type. The label names the currency and converts nothing.

  6. Clicks from the same report

    CPC is only as sound as the click count behind it. Take clicks from the report that holds the impressions.

Questions that need more than a CPM

A CPM prices impressions. Each question below needs data the form never asks for.

Question Why the calculator cannot answer it Where to look
What is a fair CPM for this campaign?
Prices depend on market, format, audience and season. The calculator holds no rate card.
Quotes from several sellers, run through this calculator on the same counting rule.
What will the site earn from my impressions?
The seller keeps what is left after fees and revenue shares. That is the seller's RPM.
RPM Calculator works it out from the seller's revenue and traffic.
What share of impressions got clicks?
CPM prices impressions. The click rate is a separate division.
CTR Calculator returns it as a percent and a decimal.
What might a website earn from display ads?
The calculator reads only the numbers you type.
Website Earning Checker models display-ad revenue for an indexed domain.
Were the impressions viewable?
Viewability is measured by an ad server or a verification vendor. The calculator counts whatever you enter.
The viewability columns of your ad server or verification report.

CPM Calculator and related tools

Four calculators around the same impressions, seen from the buyer's side and the seller's.

CPM Calculator compared with related tools
CPM Calculator This tool RPM Calculator CTR Calculator AdSense Revenue Calculator
Answers What 1,000 impressions cost, and a click when clicks are known What 1,000 pageviews or ad impressions earned a site What share of ad impressions or pageviews got clicks What pageviews could earn at a benchmark page RPM
Side of the deal Buyer: spend Seller: revenue Either side: counts only Seller: modeled revenue
You enter Cost, impressions and optional clicks Revenue and pageviews or ad impressions Clicks and ad impressions or pageviews Monthly pageviews, a category and a region
Result CPM and CPC to four decimals Page or impression RPM, and same-period revenue CTR as a percent and a decimal A monthly baseline and a yearly figure

Who prices media per thousand

Anyone holding a cost and a count of impressions.

  • Media buyers

    Use it as a cost per thousand calculator to put quotes with different totals and volumes on one scale.

  • Finance teams

    Check an invoice against the delivery report: billed cost over delivered impressions.

  • Direct-sold publishers

    Turn a flat sponsorship fee and its expected impressions into a CPM a buyer can compare.

  • Analysts

    Blend line items into one CPM, or put a per-click buy on the per-1,000 scale.

Buying terms used here

Short definitions for the words on the workbench and above.

CPM
Cost per mille, the price of 1,000 impressions. Mille means thousand.
CPC
Cost per click: total cost ÷ clicks.
Impression
One ad served. Some deals count only rendered or viewable ones.
eCPM
Effective CPM: total cost ÷ impressions × 1,000 for a buy priced some other way.
Blended CPM
Total cost ÷ total impressions × 1,000 across several line items.
Line item
One part of an order with its own price, dates and targeting.
Flight
The dates a campaign or a line item runs.
Rate card
A seller's list of prices. The calculator holds none.

Common questions

What is the CPM formula?

Cost ÷ impressions × 1,000. To calculate CPM for a buy of 2,475 that delivered 550,000 impressions: 2,475 ÷ 550,000 = 0.0045, and × 1,000 gives 4.50.

Why multiply by 1,000?

The price of one impression is a tiny fraction, such as 0.0045. Quoting it per thousand turns it into a figure people can read and compare: 4.50. That is the cost per thousand behind the name CPM.

Can I get CPC on the same page?

Yes. Fill in clicks and the readout adds CPC, cost ÷ clicks, so the page works as a CPM and CPC calculator for one buy at a time. With clicks blank, the CPC row reads Add clicks.

Why does CPC say Undefined?

Clicks were 0. A cost over zero clicks has no price per click, so the row says Undefined and a note reads “CPC is undefined when clicks are zero.” The CPM still shows.

Is the CPC here what a publisher earns per click?

No. It is what the buyer paid per click. The site receives a share of that spend after fees, which shows up in its RPM.

How do I combine CPMs from several line items?

Add the costs, add the impressions, then enter the two totals. An average of separate CPMs gives a small line item as much weight as a large one.

What is the difference between CPM and eCPM?

CPM is a price agreed per 1,000 impressions. eCPM is what any buy worked out to per 1,000 afterwards, whatever its pricing model. Enter a buy's total cost and impressions here and the figure is its eCPM.

Is there a viewable CPM mode?

No. If you enter viewable impressions as the count, the figure is cost per 1,000 viewable impressions, though the unit line still says impressions.

Can publishers use it?

Yes, as an ad CPM calculator for the buyer's price, for instance to quote a direct deal from a flat fee and its expected impressions. For what the site earned, use the RPM Calculator.

Can it work out impressions from a budget?

It works in one direction: CPM and CPC from what you enter. For the reverse, impressions = budget ÷ CPM × 1,000, and cost = CPM × impressions ÷ 1,000.

Price another buy

Enter cost and impressions in the calculator above. Add clicks for CPC.

Back to the calculator